This invention relates to flexible recording disk packs and particularly to improved techniques for developing a stacked array of flexible disks with enhanced isolation means at both ends.
In a preferred mode, a disk pack is flanked top and bottom by respective "dummy packs", each, in turn, flanked by a respective tapered flexible end-plate, the end-plates being formed simply from stacks of contiguous flexible disks, separated at their hub by a "spacer-wedge".
Workers in the subject art have constructed record storage apparatus using coaxial stacks of flexible record disks, as indicated, for instance in U.S. Pat. Nos. 3,838,462; 3,838,461; 3,969,767 and 4,167,029.
Workers are aware that the use of floppy disk packs dictate minimal cost for pack elements and associated equipment, such as partitioning means. The invention is directed toward this end, and toward accommodating a simple, non-mechanical, pneumatic, end-wise partitioning of floppy disk packs; as well as toward providing disk packs with improved flexible end-plates, better adapted to meet the usual problems and objectives. Such disk packs and associated end-wise partitioning means may be gleaned from U.S. Pat. No. 4,167,029 for "Jet Distributor for End-Wise Pneumatic Partitioning of Disk Pack" filed by H. Ragle et al. and commonly assigned herewith, this being incorporated herein by reference.
Prior "isolation packs":
In some typical prior versions of such pneumatically-partitioned floppy packs, no particular attention has been paid to "isolation means" serving to couple the ends of a floppy record-disk pack (record pack, RP) from respective end-plate means, while isolating it therefrom to prevent interference. This invention is directed toward end-plates associated with such isolation means. The invention is particularly apt for such packs wherein means are also provided for directing separation air streams axially of the pack--e.g., to the record-gaps (between record disks--to open these for transducing) as well as to the "isolation-gaps" between isolation-disks.
Thus, in one preferred embodiment the invention will be seen to comprise an axially-partitioned pack of recording disks flanked by upper and lower "dummy" (isolation) packs, these in turn flanked by respective (upper, lower) end-plates improved according to this invention. Partition holes are provided through all the disks, with annular "rim means" provided to surround these holes and afford better pneumatic isolation as well as providing a surface for disk support. Preferably, each "recording gap" (space between recording disks) has at least one of these rim means broken-away (at least partly, and preferably so as to divert air radially inward) so that the associated partition air jet will be circulated more widely as the pack rotates. Preferably, such rim means are also combined with an inner "hub-rim" to isolate the hub (spindle) area, to deflect and distribute gap air and to cooperate with rim means in creating a solid support surface for adjacent disks. Such a rim and rim means will be seen to direct and divert partitioning-air along the plane of the disks for good pneumatic partitioning.
Prior art "floppy packs":
Workers in the art have, of course, considered various techniques for providing flexible disk packs. For instance, in cited U.S. Pat. No. 3,969,767 to Griffiths et al. (and in references noted therein) attention is directed to semi-rigid washers, coaxially disposed to form an air-permeable spindle for coaxially supporting flexible record disks. Such washers have radially extending passageways and teach a rotating tubular spindle with means for supplying gas thereto to be distributed radially outward from the hub of such a pack through such air permeable washers. A rigid stabilizing plate at each axial end completes this assembly. The following IBM technical disclosure bulletins also show stacks of flexible disks with various means of partitioning suggested: IBM-TDB August '77, page 914; IBM-TDB of April 1977, page 4229 (showing "vent holes" for self-ventilation of the pack, except for provision of a relatively non-apertured central disk) and IBM-TDB of November 1974, pages 1710, 1711 (where a record pack is flanked by upper and lower dummy packs including disks separated by ventilation holes to be placed in registry along the stack). Neither this nor any other known prior art has any suggestion of any particular necessary composition or spacing of such "dummy" packs however--as taught herein.
Prior tapered end-plates ("rigid" -FIG. 5E):
The tapered rigid end-plates eP-A, eP-B of FIG. 5E are known and understood as made of molded plastic or a like rigid material and adapted to accommodate the tendency of the outer dummy disks to "flare" at their tips--if such "flaring" is not permitted (and these dummies "confined") the overall dummy pack will undesirably disturb record disks (in pack R-P).
While such rigid tapered plates serve certain desirable functions, they also suffer certain drawbacks. For instance, one set "taper angle" .alpha. (FIG. 5E) is not optimum for all conditions. That is, variations in the dimensions and/or number of the pack disks (record-and/or dummy disks) and at times in pack rotational velocity can vary the optimum taper angle. Hence, it is preferable to provide end-plates which are somewhat flexible and which can accommodate variations in "taper" of the kind suggested. (As opposed to the rigid structure of FIG. 5E which obviously is pre-set to one taper angle).
The subject invention teaches a novel "tapered", or "delta-shaped" kind of floppy end-plate, one comprised of plural stacks of abuting flexible disks, separated, adjacent their hub, by a "wedge-spacer". This structure improves considerably upon rigid end-plates, while, quite surprisingly, still providing essentially all their necessary characteristics, such as sufficient rigidity (once spun-up to the proper rpm), etc. More surprising--such a "flexible tapered plate" evidently affords a superior "pneumatic couple" better to adjacent dummy disks, allowing them to more naturally equilibrate at a "natural" position and configuration during the contemplated rotation. And, in the course of this, the "dummies" seem to "settle down" better, avoiding any adverse influence on the record pack--evidently because of the flexible, pneumatically-compressed nature of these "delta-shaped", or tapered flexible end-plates.
Prior flexible end-plates; "single stack" type (see FIG. 5B):
A "single stack" flexible end plate has been suggested (see U.S. Ser. No. 124,750, filed Feb. 26, 1980 by Herbert U. Ragle and Dean DeMoss, entitled "Improved Partitionable Pack with End plates" and commonly assigned now abandoned in favor of Ser. No. 433,180, Oct. 6, 1982, U.S. Pat. No. 4,514,778), but can be improved upon. One such problem is "dummy collapse", illustrated schematically in FIG. 5B at "outer" dummy disk 3A-a and adjacent dummy 3A-b--these being understood as "trapped" ("confined") and compressed by forces adjacent "single-stack" flexible end-plate eP during contemplated rotation. This is a problem related to the mentioned "clumping" and related anomalous action of dummy disks and can disturb the normal desired spacing and configuration of the dummy disks--and, sometimes, of adjacent record disks.
As one resolving feature, this invention teaches providing a flexible end-plate formed in a "delta-shape" with two (or more) stacks of abutting floppy disks. Such an end-plate eliminates such compression of dummy disks and related difficulties, while providing an improved "inward-tapered" surface confronting the dummy pack and adapted for better pneumatic coupling thereto.
The present invention is directed toward providing improved flexible disk packs--these being better adapted to meet the foregoing and related problems and objectives. A related object is to provide better isolation means and end-plates at both ends of a stack of floppy record disks. Another object is to do this in a mass memory disk file.
The foregoing and other features, objects and advantages according to this invention will be more fully appreciated and will become more apparent upon consideration of the following description of the preferred embodiments taken in conjunction with the attached drawings, wherein like reference indicia denote like elements.